Method of manufacturing a semiconductor device including bonding layer and adsorption layer

ABSTRACT

A semiconductor device includes a first adsorption layer, a first bonding layer, a second bonding layer, and a second adsorption layer stacked on a first substrate, and a conductive pattern structure penetrating through the first adsorption layer, the first bonding layer, the second bonding layer and the second adsorption layer. The first and second bonding layers are in contact with each other, and each of the first and second adsorption layers includes a low-κ dielectric material.

CROSS-REFERENCE TO THE RELATED APPLICATION

This is, a continuation of U.S. patent application Ser. No. 16/854,114filed Apr. 21, 2020, issued as U.S. Pat. No. 11,348,892, which is basedon and claims priority from Korean Patent Application No.10-2019-0100753, filed on Aug. 19, 2019 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND 1. Field

Methods and apparatuses consistent with example embodiment of theinventive concept relate to a semiconductor device having an adsorptionlayer with a low dielectric constant material.

2. Description of the Related Art

A semiconductor device may be manufactured by bonding substrates onwhich conductive patterns are formed, respectively. However, voids mayoccur between bonding layers bonded to each other on the substrates, andthus, the substrates may not be properly bonded.

SUMMARY

Example embodiments of the inventive concept provide semiconductordevices having improved bonding characteristics.

According to example embodiments, there is provided a semiconductordevice which may include a first adsorption layer, a first bondinglayer, a second bonding layer, and a second adsorption layer stacked ona first substrate; and a conductive pattern structure penetratingthrough the first adsorption layer, the first bonding layer, the secondbonding layer and the second adsorption layer. The first and secondbonding layers may be in contact with each other, and each of the firstand second adsorption layers may include a low-κ dielectric material.

According to example embodiments, there is provided a semiconductordevice which may include a first adsorption layer and a first bondinglayer stacked on a substrate, a first conductive pattern penetratingthrough the first adsorption layer and the first bonding layer; a secondbonding layer and a second adsorption layer stacked on the first bondinglayer and the first conductive pattern; and a second conductive patternextending through the second bonding layer and the second adsorptionlayer. The first and second bonding layers may be in contact with eachother, and the first and second conductive patterns may be in contactwith each other Each of the first and second adsorption layers mayinclude a low-κ dielectric material

According to example embodiments, there is provided a semiconductordevice which may include: a first structure including a first insulatinginterlayer, a first diffusion barrier layer, a first adsorption layerand a first bonding layer stacked on a substrate; a first conductivepattern penetrating through the first structure, a second structureincluding a second bonding layer, a second adsorption layer, a seconddiffusion barrier layer and a second insulating interlayer stacked onthe first structure and the first conductive pattern; and a secondconductive pattern penetrating through the second structure. The firstand second bonding layers may be in contact with each other, and thefirst and second conductive patterns may be in contact with each other.Each of the first and second adsorption layers may include a low-κdielectric material, and may further include an air gap extendingtherethrough.

In a method of manufacturing a semiconductor device, an adsorption layerincluding a low-κ dielectric material may be further formed between aninsulating interlayer and a bonding layer Since the adsorption layer mayhave a lower density than the bonding layer, water molecules formed on asurface of the bonding layer may be penetrated into the adsorptionlayer, so that bonding strength of the bonding layer may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 7 are cross-sectional views illustrating stages of a methodof manufacturing a semiconductor device in accordance with exampleembodiments.

FIGS. 8 to 12 are and cross-sectional views illustrating stages of amethod of manufacturing a semiconductor device in accordance withexample embodiments.

FIGS. 13 to 16 are and cross-sectional views illustrating semiconductordevices in accordance with example embodiments.

FIGS. 17 to 26 are and cross-sectional views illustrating stages of amethod of manufacturing a semiconductor device, more specifically, animage sensor in accordance with example embodiments.

DESCRIPTION OF EMBODIMENTS

The embodiments described herebelow are all exemplary, and thus, theinventive concept is not limited to these embodiments disclosed belowand may be realized in various other forms. An embodiment provided inthe following description is not excluded from being associated with oneor more features of another example or another embodiment also providedherein or not provided herein but consistent with the inventive concept.For example, even if matters described in a specific example are notdescribed in a different example thereto, the matters may be understoodas being related to or combined with the different example, unlessotherwise mentioned in descriptions thereof.

It will be understood that, although the terms first, second, third,fourth etc. may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the present inventive concept.

It will be understood that when an element or layer is referred to asbeing “over,” “above,” “on,” “connected to” or “coupled to” anotherelement or layer, it can be directly over, above, on, connected orcoupled to the other element or layer or intervening elements or layersmay be present. In contrast, when an element is referred to as being“directly over,” “directly above,” “directly on,” “directly connectedto” or “directly coupled to” another element or layer, there are nointervening elements or layers present. Like numerals refer to likeelements throughout.

Spatially relative terms, such as “beneath,” “below,” “lower,” “under,”“on,” “over,” “above,” “upper” and the like, may be used herein for easeof description to describe one element's or feature's relationship toanother element(s) or feature(s) as illustrated in the figures. It willbe understood that the spatially relative terms are intended toencompass different orientations of the device in use or operation inaddition to the orientation depicted in the figures. For example, if thedevice in the figures is turned over, elements described as “below” or“beneath” other elements or features would then be oriented “above” theother elements or features. Thus, the term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

Semiconductor devices and methods of manufacturing the same inaccordance with embodiments will be described more fully hereinafterwith reference to the accompanying drawings.

FIGS. 1 to 7 are cross-sectional views illustrating stages of a methodof manufacturing a semiconductor device in accordance with embodiments.

Referring to FIG. 1 , a first insulating interlayer 110, a firstadsorption layer 120 and a first bonding layer 130 may be stacked on afirst substrate 100.

The first substrate 100 may include semiconductor materials, e.g.,silicon, germanium, silicon-germanium, etc., or III-V compounds e.g.,GaP, GaAs, GaSb, etc., not being limited thereto. According toembodiments, the first substrate 100 may be a silicon-on-insulator (SOI)substrate or a germanium-on-insulator (GOI) substrate. According to anembodiment, the first substrate 100 may be doped with p-type impurities.

Although not shown, semiconductor elements such as transistors, contactplugs, wirings, capacitors, and the like may be formed on the firstsubstrate 100.

The first insulating interlayer 110 may include an oxide, e.g., tetraethoxysilane (TEOS), not being limited thereto.

The first adsorption layer 120 may include a material having a lowdielectric constant, that is, a low-κ dielectric material. The materialincluded in the first adsorption layer 120 may be formed of at least oneselected from the group consisting of SiOF (fluorous silica gel; FSG),SiCOH, hydrogen silsesquioxane (HSQ), methyl silsesquioxane (MSQ),poly(arylene ether)(PAE), polyimide, parylene-N, parylene-F,Teflon(polytetrafluoroethlene; PTFE), amorphous carbon, amorphousfluorocarbon, porous SiCOH, porous MSQ, and porous PAE.

The first bonding layer 130 may include a material such as siliconcarbonitride (SiCN) or silicon oxide (SiO₂), not being limited thereto.According to embodiments, in the case that the first bonding layer 130includes silicon carbonitride (SiCN), the first bonding layer 130 mayhave a thickness of about 500 Å or less, and in the case that the firstbonding layer 130 includes silicon oxide (SiO₂), the first bonding layer130 may have a thickness of about 1000 Å or less.

In embodiments, the first adsorption layer 120 may have a lower densitythan the first bonding layer 130. Also, the first adsorption layer 120may have a smaller thickness than the first insulating interlayer 110.

Referring to FIG. 2 , a first etch stop layer 140 may be formed on thefirst bonding layer 130, and at least one first opening 145 may beformed to penetrate into an upper portion of the first insulatinginterlayer 110 through the first etch stop layer 140, the first bondinglayer 130, and the first adsorption layer 120.

According to embodiments, the first etch stop layer 140 may include anitride, e.g., silicon nitride (SiN) or silicon carbonitride (SiCN).

According to embodiments, a plurality of first openings 145 may beformed along a horizontal direction substantially parallel to an uppersurface of the first substrate 100.

Referring to FIG. 3 , a first conductive layer 150 filling the firstopening 145 may be formed on the first etch stop layer 140.

The first conductive layer 150 may include a metal, e.g., tungsten,titanium, tantalum, etc.

Referring to FIG. 4 , a polishing process may be performed until anupper surface of the first bonding layer 130 may be exposed.Accordingly, the first conductive layer 150 may be transformed into afirst conductive pattern 155 remaining on the first opening 145, and thefirst etch stop layer 140 may be removed.

According to an embodiment, an upper surface of the conductive pattern155 may be formed lower than the upper surface of the first bondinglayer 130.

According to embodiments, the polishing process may include a chemicalmechanical polishing (CMP) process.

Referring to FIG. 5 , processes substantially the same as or similar tothe processes described with reference to FIGS. 1 to 4 may be performed.

In this process, a second insulating interlayer 210, a second adsorptionlayer 220 and a second bonding layer 230 may be stacked on a secondsubstrate 200. Next, a second etch stop layer (not shown) may be formedon the second bonding layer 230, and at least one second opening may beformed to penetrate through the second etch stop layer, the secondbonding layer 230, the second adsorption layer 220, the secondinsulating interlayer 210 and the second substrate 200. Further, asecond conductive layer filling the second opening may be formed on thesecond etch stop layer followed by a polishing process performed untilan upper surface of the second bonding layer 230 is exposed And then, asecond conductive pattern 255 may be formed in the second opening, andthe second etch stop layer may be removed.

FIG. 5 describes that the second opening penetrates through the secondinsulating interlayer 210 and the second substrate 200. However, theinventive concept may not be limited thereto. According to anembodiment, the second opening may be formed not to penetrate throughthe second insulating interlayer 210 and the second substrate 200, butto penetrate into only an upper portion of the second insulatinginterlayer 210.

According to embodiments, the second substrate 200, the secondinsulating interlayer 210, the second adsorption layer 220, the secondbonding layer 230, the second etch stop layer and the second conductivelayer may include substantially the same material as the first substrate100, the first insulating interlayer 110, the first adsorption layer120, the first bonding layer 130, the first etch stop layer 140 and thefirst conductive layer 150, respectively.

Accordingly, the second adsorption layer 220 may have a lower densitythan the second bonding layer 230, and may have a smaller thickness thanthe second insulating interlayer 210.

Referring to FIG. 6 , after upending the second substrate 200 so thatthe second bonding layer 230 faces downward, the upended secondsubstrate 200 may be disposed on the first substrate 100, and thus, thefirst and second bonding layers 130 and 230 may contact each other. Thefirst conductive pattern 155 and the second conductive pattern 255 maynot contact each other, but may be at least partially overlapped along avertical direction substantially perpendicular to the upper surface ofthe first substrate 100.

FIG. 6 describes that each of a surface of the first bonding layer 130opposite to the second substrate 200 and a surface of the second bondinglayer 230 opposite to the first substrate 100 has a uniform surface, andall surfaces of the first and second bonding layers 130 and 230, exceptfor portions thereof where the first and second conductive patterns 155and 255, are formed to contact each other. However, the inventiveconcept is limited thereto. According to an embodiment, the surface ofthe first bonding layer 130 opposite to the second substrate 200 and/orthe surface of the second bonding layer 230 opposite to the firstsubstrate 100 may not have uniform surfaces, and in this case, thesurfaces of the first and second bonding layers 130 and 230 may notpartially contact each other.

Also, FIG. 6 describes that the first conductive pattern 155 and thesecond conductive pattern 255 exactly overlap each other in the verticaldirection. However, the inventive concept may not be limited thereto.According to an embodiment, the first conductive pattern 155 and thesecond conductive pattern 255 may only partially overlap in the verticaldirection.

According to an embodiment, an empty space may be formed between thefirst conductive pattern 155 and the second conductive pattern 255, andgases may be trapped in the empty space.

Referring to FIG. 7 , a heat treatment process may be performed betweenthe first substrate 100 and the second substrate 200, and the first andsecond substrates 100 and 200 may be bonded to each other.

Accordingly, the first bonding layer 130 on the first substrate 100 andthe second bonding layer 230 on the upended second substrate 200 may bebonded and merged with each other. Also, each of the first conductivepattern 155 and the second conductive pattern 255 may be thermallyexpanded by the heat treatment process to increase its volume, and thus,may be bonded and merged with each other. The first and secondconductive patterns 155 and 255 merged with each other altogether mayform a first conductive pattern structure.

According to embodiments, the heat treatment process may be performed,e.g., at a temperature of about 400° C.

As described above, the first adsorption layer 120 may be formed underthe first bonding layer 130 on the first substrate 100, and the firstadsorption layer 120 may have a lower density than the first bondinglayer 130, so that gases generated by the heat treatment process maypenetrate through the first bonding layer 130, and may be adsorbed tothe first adsorption layer 120.

Particularly, strong covalent bonds having a hydroxyl group (—OH) may beformed between silicon (Si) on the surface of the first bonding layer130 and oxygen (O) atoms in the air, and water molecules may be formedby the hydroxyl group (—OH). When the water molecules are vaporized bythe heat treatment process subsequently performed, the vaporized watermolecules may penetrate through the first bonding layer 130 and may beabsorbed into the first adsorption layer 120 by the density differencebetween the first bonding layer 130 and the first adsorption layer 120.Similar to the first substrate 100, the second adsorption layer 220 maybe formed on the second bonding layer 230 on the upended secondsubstrate 200, and the second adsorption layer 220 may have a lowerdensity than the second bonding layer 230, so that gases generated bythe heat treatment process may penetrate through the second bondinglayer 230 and may be adsorbed to the second adsorption layer 220.Accordingly, the vaporized water molecules may not remain between thesurface of the first bonding layer 130 opposite to the second substrate200 and the surface of the second bonding layer 230 opposite to thefirst substrate 100, and thus a void may not be formed.

In addition, since gases of metal components trapped in the empty spacebetween the first conductive pattern 155 and the second conductivepattern 255, or released as the first and second conductive patterns 155and 255 are thermally expanded may also penetrate through the first andsecond bonding layers 130 and 230, and may be absorbed into the firstand second adsorption layers 120 and 220, bonding strength of the firstand second bonding layers 130 and 230 may be improved.

FIGS. 8 to 12 are and cross-sectional views illustrating stages of amethod of manufacturing a semiconductor device in accordance withembodiments.

The method may include processes substantially the same as or similar tothe processes described with reference to FIGS. 1 to 7 , except thateach of insulating interlayers corresponding to the first and secondinsulating interlayers 110 and 120 includes at least one air gap.Accordingly, duplicate descriptions thereon are omitted herein.

Referring to FIG. 8 , a third insulating interlayer 310 may be formed ona third substrate 300, and a first photoresist pattern 320 including atleast one third opening 325 may be formed on the third insulatinginterlayer 310.

A plurality of third openings 325 may be formed along the horizontaldirection, according to embodiments.

According to embodiments, the third opening 325 may have a circularshape or an elliptical shape in the plan view, and may have a circularpillar shape or an elliptical shape as a whole, not being limitedthereto.

According to embodiments, the third insulating interlayer 310 mayinclude the material substantially the same as the first and secondinsulating interlayers 110 and 210.

Referring to FIG. 9 , the third insulating interlayer 310 may be etchedby performing an etching process using the first photoresist pattern 320as an etching mask, and thus, at least one fourth opening 315 may beformed on the third insulating interlayer 310.

A plurality of fourth openings 315 may be formed along the horizontaldirection.

Referring to FIG. 10 , a third bonding layer 330 and a third etch stoplayer 340 may be stacked on the third insulating interlayer 310.

The fourth opening 315 may not be filled with the third bonding layer330, and the fourth opening 315 will be referred to as at least onefirst air gap 315 hereinafter.

According to embodiments, the third bonding layer 330 may includesubstantially the same material as the first and second bonding layers130 and 230, and the third etch stop layer 340 may include substantiallythe same material as the first etch stop layer 140 and the second etchstop layer.

Referring to FIG. 11 , processes substantially the same as or similar tothe processes described with reference to FIGS. 2 to 4 may be performed.

At least one fifth opening 335 may be formed to penetrate through thethird etch stop layer 340, the third bonding layer 330 and an upperportion of the third insulating interlayer 310. A third conductive layerfilling the fifth opening 335 may be formed on the third etch stop layer340. A polishing process may be performed until an upper surface of thethird bonding layer 330 may be exposed. A third conductive pattern 355may be formed in the fifth opening 335, and the third etch stop layer340 may be removed.

FIG. 11 describes that the fifth opening 335 does not penetrate throughthe third insulating interlayer 310 and the third substrate 300, butpenetrate into only the upper portion of the third insulating interlayer310. However, the inventive concept may not be limited thereto, and thefifth opening 335 may penetrate through the third insulating interlayer310 and the third substrate 300.

The fifth opening 335 may be formed to vertically overlap at least oneof the first air gaps 315 on the third insulating interlayer 310 to beconnected therewith. Accordingly, a lower surface of the thirdconductive pattern 355 formed in the fifth opening 335 may be exposed bythe at least one of the first air gaps 315.

The third conductive layer may include substantially the same materialas the first conductive layer 150 and the second conductive layer.

Referring to FIG. 12 , after performing processes substantially the sameas or similar to the processes described with reference to FIGS. 8 to 11, processes substantially the same as or similar to the processesdescribed with reference to FIGS. 6 and 7 may be performed.

A fourth insulating interlayer 410 may be formed on a fourth substrate400, and a second photoresist pattern (not shown) including, at leastone sixth opening (not shown) may be formed on the fourth insulatinginterlayer 410. The fourth insulating interlayer 410 may be etched byperforming an etching process using the second photoresist pattern as anetching mask, and thus, at least one seventh opening (not shown) may beformed on the fourth insulating interlayer 410. A fourth bonding layer430 and a fourth etch stop layer (not shown) may be stacked on thefourth insulating interlayer 410. The seventh opening may not be filledwith the fourth bonding layer 430 and the fourth etch stop layer, theseventh opening will be referred to as at least one second air gap 415hereinafter.

At least one eighth opening may be formed to penetrate through thefourth etch stop layer, the fourth bonding layer 430, the fourthinsulating interlayer 410 and the fourth substrate 400, and a fourthconductive layer filling the eighth opening may be formed on the fourthetch stop layer. A polishing process may be performed until an uppersurface of the fourth bonding layer 430 may be exposed. A fourthconductive pattern 455 may be formed in the eighth opening, and thefourth etch stop layer may be removed.

FIG. 12 describes that the eighth opening penetrates through the fourthinsulating interlayer 410 and the fourth substrate 400. However, theinventive concept may not be limited thereto. The eighth opening may beformed not to penetrate through the fourth insulating interlayer 410 andthe fourth substrate 400, but penetrate into only an upper portion ofthe fourth insulating interlayer 410.

After upending the fourth substrate 400 so that the fourth bonding layer430 faces downward, the upended fourth substrate 400 may be disposed onthe third substrate 300, and thus the third and fourth bonding layers330 and 430 may contact each other. The third conductive pattern 355 andthe fourth conductive pattern 455 may not contact each other, but may beat least partially overlapped along a vertical direction substantiallyperpendicular to the upper surface of the third substrate 300.

A heat treatment process may be performed between the third substrate300 and the fourth substrate 400, and the third and fourth substrates300 and 400 may be bonded to each other.

Accordingly, the third and fourth bonding layers 330 and 430 may bebonded and merged with each other. Also, each of the third and fourthconductive patterns 355 and 455 may be thermally expanded by the heattreatment process to increase its volume, and thus, may be bonded andmerged with each other to form a second conductive pattern structure.

As described above, the first and second air gaps 315 and 415 may beformed in the third and fourth insulating interlayers 310 and 410 formedon the third and fourth substrates 300 and 400, respectively, so thatgases generated by the heat treatment process may move into the firstand second air gaps 315 and 415.

In addition, since gases of metal components trapped in the empty spacebetween the third and fourth conductive patterns 355 and 455, orreleased as the third and fourth conductive patterns 355 and 455 arethermally expanded may be absorbed into the first and second air gaps315 and 415, bonding strength of the third and fourth bonding layers 330and 430 may be improved.

FIGS. 13 to 16 are and cross-sectional views illustrating semiconductordevices in accordance with embodiments.

The semiconductor devices are substantially the same as or similar tothe semiconductor devices described with reference to FIGS. 7 and 12 ,except for some components. Accordingly, like reference numerals referto like elements, and duplicate descriptions thereon are omitted herein.

Referring to FIG. 13 , an upper surface of the first conductive pattern155 may contact a lower surface of the second conductive pattern 255 anda lower surface of the second bonding layer 230 together. This isbecause, when the second substrate 200 is upended so that the secondbonding layer 230 faces downward, and the upended second substrate 200is disposed on the first substrate 100, the first conductive pattern 155formed on the first substrate 100 and the second conductive pattern 255formed to penetrate through the upended second substrate 200 are notcompletely overlapped with each other, but are partially overlapped inthe vertical direction. Accordingly, after performing the heat treatmentprocess, the upper surface of the first conductive pattern 155 and thelower surface of the second conductive pattern 255 may be partially incontact with each other instead of being entirely in contact with eachother.

Although not shown in FIG. 13 , at least one of the first and secondinterlayer insulating layers may have at least one air gap such as theair gaps 315 and/or 415 shown in FIG. 12 to increase bonding strength ofthe first and second bonding layers 130 and 230, according to anembodiment.

Referring to FIG. 14 , the first and second adsorption layers 120 and220 may include at least one third air gap 125 and at least one fourthair gap 225 penetrating through them, respectively.

Accordingly, the first and second adsorption layers 120 and 220 may havea smaller density than when the third and fourth air gaps 125 and 225are not formed as shown in FIG. 7 , and gases generated by thesubsequent heat treatment process may be better adsorbed to the firstand second adsorption layers 120 and 220.

Referring to FIG. 15 , a first diffusion barrier layer 117 may befurther formed between the first insulating interlayer 110 and the firstadsorption layer 120 on the first substrate 100, and a second diffusionbarrier layer 217 may be further formed between the second insulatinginterlayer 210 and the second adsorption layer 220 on the secondsubstrate 200. Thus gases absorbed into the first and second adsorptionlayers 120 and 220 may be prevented from being diffused into the firstand second insulating interlayers 110 and 220 adjacent to them,respectively.

According to embodiments, each of the first and second diffusion barrierlayers 117 and 217 may have a higher density than each of the first andsecond adsorption layers 120 and 220. According to an embodiment, thefirst and second diffusion barrier layers 117 and 217 may includesubstantially the same material as the first and second bonding layers130 and 230. According to an embodiment, the first and second diffusionbarrier layers 117 and 217 may include different material from the firstand second bonding layers 130 and 230.

Referring to FIG. 16 , the first and second adsorption layers 120 and220 may include third and fourth air gaps 125 and 225 penetratingthrough them, respectively. Further, a first diffusion barrier layer 117may be further formed between the first insulating interlayer 110 andthe first adsorption layer 120 on the first substrate 100, and a seconddiffusion barrier layer 217 may be further formed between the secondinsulating interlayer 210 and the second adsorption layer 220 on thesecond substrate 200.

FIG. 16 illustrates that the first conductive pattern 155 is formed notto penetrate through the first insulating layer 110 and the firstsubstrate 100. However, the inventive concept may not be limitedthereto, and thus, the first conductive pattern 155 may be formed topenetrate through the first insulating layer 110, or the firstinsulating layer 110 and the first substrate 100.

FIGS. 17 to 26 are and cross-sectional views illustrating stages of amethod of manufacturing an image sensor in accordance with embodiments.

The method may include processes substantially the same as or similar tothe processes described with reference to FIGS. 1 to 7 . Accordingly,like reference numerals refer to like elements, and duplicatedescriptions thereon are omitted herein.

Hereinafter, two directions substantially parallel to an upper surfaceof a substrate and intersecting with each other are defined as first andsecond directions, respectively, and a direction substantially verticalto the upper surface of the substrate is defined as a third direction.According to embodiments, the first and second directions may beorthogonal to each other.

Referring to FIG. 17 , at least one pixel isolation pattern (not shown),at least one through via 530 and at least one photodiode 540 may beformed in a fifth substrate 500 which includes first to third regions I,II and III.

The fifth substrate 500 may include substantially the same material asthe first to fourth substrates 100, 200, 300 and 400. According to anembodiment, the fifth substrate 500 may be doped with p-type impurities.

According to embodiments, the first region I may be a region in whichpixels may be formed, the second region II may be a region in which padsfor inspecting the electrical characteristics of the pixels may beformed, and the third region III may be an input/output (I/O) region inwhich conductive structures for inputting/outputting electrical signalsto/from the pixels may be formed. Hereinafter, the first to thirdregions I, II and III may be used as a concept including not only aninside of the fifth substrate 500, but also upper and lower spacesthereof.

The pixel isolation pattern and the through via 530 may be formed byforming first and second trenches extending in the third directiondownwardly within the first region I of the fifth substrate 500, andfilling the first and second trenches, respectively. The pixel isolationpattern and the through via 530 altogether may define a region in whicha unit pixel may be formed, and a plurality of unit pixel regions may bearranged along each of the first and second directions within the firstregion I.

According to embodiments, the pixel isolation pattern may include e.g.,an insulating material such as oxide or nitride, or a semiconductormaterial such as polysilicon. According to other embodiments, the pixelisolation pattern may include, e.g., doped polysilicon, or a conductivematerial such as metal, metal nitride, etc.

The through via 530 may include a first insulation layer 510 on an innerwall of the second trench and a fifth conductive pattern 520 formed onthe first insulation layer 510 to fill a remaining portion of the secondtrench.

According to embodiment, the photodiode 540 may have a structure inwhich a first impurity region doped with an n-type impurity and a secondimpurity region doped with a p-type impurity may be stacked.

An isolation pattern (not shown), transistors (not shown) and a floatingdiffusion (FD) region (now shown) may be further formed at an upperportion of the fifth substrate 500. The transistors may include, e.g., atransfer transistor, a source follower transistor, a reset transistor,and a select transistor. The FD region may be doped with impurities of aconductivity type different from that of the fifth substrate 500, thatis, an n-type impurity.

Referring to FIG. 18 , a fifth insulating interlayer 580 containing atleast one first wiring structure 550, at least one second wiringstructure 560 and at least one third wiring structure 570 therein may beformed on the fifth substrate 500.

The first to third wiring structures 550, 560 and 570 may be formed inthe first to third regions I, II and III, respectively. According toembodiments, the first wiring structure 550 may be formed to overlap thethrough via 530 and/or the pixel isolation pattern in the thirddirection. However, the inventive concept may not be limited thereto,and may be formed in various different layouts.

Also, each of the first to third wiring structures 550, 560 and 570 maybe formed at a plurality of levels. The first to third wiring structures550, 560 and 570 may be electrically connected with one another throughfirst vias (not shown) formed in the fifth insulating interlayer 580.According to embodiments, the first to third wiring structures 550, 560and 570 and the first vias may be formed by a dual damascene process ora single damascene process.

According to embodiments, the through via 530 may be electricallyconnected to the first wiring structure 550 through a first contact plug590 in the fifth insulating interlayer 580. The FD region may also beelectrically connected to the first wiring structure 550 through asecond contact plug (now shown) in the fifth insulating interlayer 580.

After stacking a fifth adsorption layer 600 and a fifth bonding layer610 on the fifth insulating interlayer 580, processes substantially thesame as or similar to the processes described with reference to FIGS. 2to 4 may be performed to form a sixth conductive pattern 620 penetratingthrough the fifth adsorption layer 600 and the fifth bonding layer 610and being electrically connected to the third wiring structure 570.

Referring to FIG. 19 , a sixth insulating interlayer 730 containing atleast one fourth wiring structure 710 and at least one fifth wiringstructure 720 therein may be formed on a sixth substrate 700.

The fourth and fifth wiring structures 710 and 720 may be formed in thesecond and third regions II and III, respectively. Each of the fourthand fifth wiring structures 710 and 720 may be formed at a plurality oflevels. The fourth and fifth wiring structures 710 and 720 may beelectrically connected with each other through second vias (not shown)formed in the sixth insulating interlayer 730. According to embodiments,the fourth and fifth wiring structures 710 and 720 and the second viasmay be formed by a dual damascene process or a single damascene process.

After stacking a sixth adsorption layer 740 and a sixth bonding layer750 on the sixth insulating interlayer 730, processes substantially thesame as or similar to the processes described with reference to FIGS. 2to 4 may be performed to form a seventh conductive pattern 760penetrating through the sixth adsorption layer 740 and the sixth bondinglayer 750 and being electrically connected to the fifth wiring structure720.

Referring to FIG. 20 , by performing processes substantially the same asor similar to the processes described with reference to FIGS. 6 and 7 ,the fifth substrate 500 may be upended so that the fifth bonding layer610 faces downward, and the fifth and sixth bonding layers 610 and 750may contact each other. An upper portion of the upended fifth substrate500 may be removed.

The sixth conductive pattern 620 and the seventh conductive pattern 760may be disposed to be overlapped with each other, and may be thermallyexpanded to contact each other by a heat treatment process. Accordingly,the sixth and seventh conductive patterns 620 and 760 may beelectrically connected with each other, and the third and fifth wiringstructures 570 and 720 electrically connected to them, respectively, mayalso be electrically connected with each other.

According to embodiments, the upper portion of the upended fifthsubstrate 500 may be removed by a polishing process, e.g., a grindingprocess. Accordingly, the pixel isolation pattern and the through via530 may be exposed.

Particularly, a portion of the first insulation layer 510 covering anupper surface of the fifth conductive pattern 520 in the through via 530may be also removed by the polishing process to form a first insulationpattern 515. Accordingly, the through via 530 may include the fifthconductive pattern 520 and the first insulation pattern 515 covering asidewall of the fifth conductive pattern 520.

Referring to FIG. 21 , a third trench 762 penetrating into an upperportion of the fifth substrate 500 adjacent to the through via 530, afourth trench 764 adjacent to the third trench 762 and penetratingthrough the fifth substrate 500 to expose the second wiring structure560, and a fifth trench 766 penetrating through the fifth substrate 500and into the fifth insulating interlayer 580 to expose the third wiringstructure 570 may be formed.

The third to fifth trenches 762, 764 and 766 may be formed on the upperportion of the fifth substrate 500 by forming an etching mask, e.g., aphotoresist pattern and performing a dry etching process using theetching mask. The third and fourth trenches 762 and 764 may be formed inthe second region II, and the fifth trench 766 may be formed in thethird region III.

According to embodiments, the fifth trench 766 may have a greater widththan that of the fourth trench 764.

Referring to FIG. 22 , an eighth conductive pattern 772 may be formed onthe fifth substrate 500 to fill the third trench 762, and a third via774 may be formed to fill the fourth trench 764 and contact a lowersurface of the eighth conductive pattern 772 extended over the fourthtrench 764. FIG. 22 further shows that a fourth via 776 may be formed onan inner wall of the fifth trench 766 and the fifth substrate 500.

The eighth conductive pattern 772 may fill the third trench 762, and maybe formed on the fifth substrate 500 adjacent thereto. The third via 774may fill the fourth trench 764, and may contact the second wiringstructure 560 thereunder and the eighth conductive pattern 772 thereon.

According to embodiments, the eighth conductive pattern 772 may includea metal, e.g., tungsten, titanium, tantalum, etc.

A portion of the eighth conductive pattern 772 filling in the thirdtrench 762 may have a concave upper surface depending on the depth ofthe third trench 762, and a ninth conductive pattern 780 may be furtherformed on the concave upper surface of the eighth conductive pattern772. Accordingly, the eighth and ninth conductive patterns 772 and 780may form a pad 785.

According to an embodiment, the ninth conductive pattern 780 may includea metal, e.g., aluminum.

Referring to FIG. 23 , after forming a seventh insulating interlayer 790on the fifth substrate 500 to cover the pad 785 and the fourth via 776,a polishing stop layer 800 and an eighth insulating interlayer 810 maybe formed on the seventh insulating interlayer 790.

According to embodiments, the seventh insulating interlayer 790 may notentirely fill the fifth trench 766, and thus may have a concave uppersurface in the fifth trench 766. Also, the seventh insulating interlayer790 may have a convex upper surface on the pad 785 on the fifthsubstrate 500. Accordingly, the seventh insulating interlayer 790 mayhave a uneven upper surface rather than a flat, even surface.

Accordingly, the polishing stop layer 800 and the eighth insulatinginterlayer 810 stacked on an upper surface of the seventh insulatinginterlayer 790 may also have uneven upper surfaces rather than flat,even surfaces. The polishing stop layer 800 may be formed to have athickness smaller than those of the seventh and eighth insulatinginterlayers 790 and 810, and thus, may be conformally formed on theseventh insulating interlayer 790 not to entirely fill the fifth trench766. However, the eighth insulating interlayer 810 may be formed to havea sufficient thickness to entirely fill a remaining portion of the fifthtrench 766.

According to embodiments, the polishing stop layer 800 may have amaterial having a high polishing selectivity with respect to the eighthinsulating interlayer 810, e.g., a nitride such as silicon nitride(SiN), silicon oxynitride (SiON), etc., or a carbide such as siliconcarbide (SiC), silicon oxycarbide (SiOC), etc.

Referring to FIG. 24 , a polishing process may be performed on theeighth insulating interlayer 810 until the polishing stop layer 800 maybe exposed.

The polishing stop layer 800 may have the uneven upper surface, andthus, after the polishing process, the eighth insulating interlayer 810may not be entirely removed, but a portion thereof may remain on thepolishing stop layer 800.

Until the polishing stop layer 800 except for a portion thereof in thefifth trench 766 may be entirely removed, the polishing stop layer 800,the remaining portion of the eighth insulating interlayer 810, and theseventh insulating interlayer 790 may be removed.

After the polishing process, in addition to the fourth via 776 and theseventh insulating interlayer 790, the polishing stop layer 800 and theeighth insulating interlayer 810 may remain to form a polishing stoppattern 805 and a second insulation pattern 815, respectively, in thefifth trench 766.

After forming a ninth insulating interlayer 820 on the seventhinsulating interlayer 790, the polishing stop pattern 805 and the secondinsulation pattern 815, at least one third contact plug 830 may beformed through the seventh and ninth insulating interlayers 790 and 820to contact the through via 530.

Referring to FIG. 25 , after removing the ninth insulating interlayer820 to expose upper surfaces of the seventh insulating interlayer 790,the polishing stop pattern 805 and the second insulation pattern 815,and an upper portion of the third contact plug 830, a third insulationpattern 845 may be formed thereon.

A color filter 850 may be formed through the third insulation pattern845 and the seventh insulating interlayer 790. According to embodiments,the color filter 850 may be formed within the unit pixel region definedby the pixel isolation pattern and the through via 530, and may notoverlap the pixel isolation pattern and the through via 530 in the thirddirection.

According to embodiments, the color filter 850 may be a red filter or ablue filter.

After forming a fourth insulation layer 860 on the third insulationpattern 845 and the color filter 850, the fourth insulation layer 860may be planarized until an upper surface of the third contact plug 830may be exposed.

Referring to FIG. 26 , a first transparent electrode 870, an organiclayer 880, a second transparent electrode 890, a protective layer 900and a microlens 910 may be stacked on the fourth insulation layer 860,the third insulation pattern 845 and the third contact plug 830 in thefirst region I.

According to embodiments, the first transparent electrode 870 may beformed correspondingly to each of the unit pixel regions, and maycontact the upper surface of the third contact plug 830. A sidewall ofthe first transparent electrode 870 may be covered by a fifth insulationlayer 875.

According to embodiments, the organic layer 880, the second transparentelectrode 890 and the protective layer 900 may be formed over the entirefirst region I, and the microlens 910 may be formed correspondingly toeach of the unit pixel regions. The first transparent electrode 870, theorganic layer 880 and the second transparent electrode 890 stacked inthe third direction may form an organic photodiode.

The first and second transparent electrodes 870 and 890 may include,e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO),tin dioxide (SnO₂), antimony-doped tin oxide (ATO), antimony-doped zincoxide (AZO), gallium-doped zinc oxide (GZO), titanium dioxide (TiO₂),fluorine-doped tin oxide (FTO), etc. The organic layer 880 may includean organic material in which an electron donor and an electron acceptormay be mixed with each other. For example, the organic layer 880 mayinclude a plurality of layers in which a p-type semiconductor materialand an n-type semiconductor material may form a pn-junction or a bulkhetero-junction. The protective layer 900 may include an oxide, e.g.,silicon oxide.

Although not shown, upper wiring structures (not shown) may be furtherformed to be electrically connected to the pad 785 and the fourth via774 in the second and third regions II and III.

As described above, the fifth and sixth adsorption layers 600 and 740may be formed under the fifth and sixth bonding layers 610 and 750,respectively, formed on the fifth and sixth substrates 500 and 700,respectively. The fifth and sixth adsorption layers 600 and 740 may havea lower density than the fifth and sixth bonding layers 610 and 750, sothat gases generated by the heat treatment process may penetrate throughfifth and sixth bonding layers 610 and 750, and may be adsorbed to thefifth and sixth adsorption layers 600 and 740.

In addition, since gases of metal components trapped in an empty spacebetween the sixth and seventh conductive patterns 620 and 760, orreleased as the sixth and seventh conductive patterns 620 and 760 arethermally expanded may be absorbed into the fifth and sixth adsorptionlayers 600 and 740, bonding strength of the fifth and sixth bondinglayers 610 and 750 may be improved.

The above semiconductor device may be applied to not only complementarymetal-oxide-semiconductor image sensors (CISs), but also volatile memorydevices such as dynamic random access memory (DRAM) devices,non-volatile memory devices such as flash memory devices, andsemiconductor packages such as high-bandwidth memories (HBMs).

As described above, although the inventive concept has been describedwith reference to example embodiments, those skilled in the art willreadily appreciate that many modifications are possible in the exampleembodiments without materially departing from the novel teachings andadvantages of the present inventive concept.

What is claimed is:
 1. A method of manufacturing a semiconductor device,the method comprising: sequentially forming a first interlayerinsulating layer, a first adsorption layer and a first bonding layer ona first substrate, the first adsorption layer including a low-kdielectric material and having a density lower than a density of thefirst bonding layer; forming a first conductive pattern through thefirst bonding layer, the first adsorption layer and a portion of thefirst interlayer insulating layer; sequentially forming a secondinterlayer insulating layer, a second adsorption layer and a secondbonding layer on a second substrate, the second adsorption layerincluding a low-k dielectric material and having a density lower than adensity of the second bonding layer; forming a second conductive patternthrough the second bonding layer, the second adsorption layer and aportion of the second interlayer insulating layer; disposing the secondsubstrate on the first substrate so that the first and second bondinglayers contact each other, the first and second conductive patterns atleast partially overlap with each other in a vertical directionsubstantially perpendicular to an upper surface of the first substrate;and performing a heat treatment process on the first and secondsubstrates, wherein forming the first conductive pattern includes:forming a first etch stop layer on the first bonding layer; forming afirst opening through the first etch stop layer, the first bondinglayer, the first adsorption layer and the portion of the firstinterlayer insulating layer; forming a first conductive layer on thefirst etch stop layer to fill the first opening; and performing apolishing process on the first conductive layer until the first etchstop layer is removed and an upper surface of the bonding layer isexposed.
 2. The method of claim 1, wherein the first and secondconductive patterns do not contact each other before performing the heattreatment process.
 3. The method of claim 2, wherein the first andsecond conductive patterns contact each other after performing the heattreatment process.
 4. The method of claim 1, wherein the forming thesecond conductive pattern includes: forming a second etch stop layer onthe second bonding layer; forming a second opening through the secondetch stop layer, the second bonding layer, the second adsorption layerand the portion of the second interlayer insulating layer; forming asecond conductive layer on the second etch stop layer to fill the secondopening; and performing a polishing process on the second conductivelayer until the second etch stop layer is removed and an upper surfaceof the second bonding layer is exposed.
 5. The method of claim 1,wherein the lower dielectric material included in the first adsorptionlayer or the second adsorption layer comprises at least one selectedfrom the group consisting of SiOF (fluorous silica gel, FSG), SiCOH,hydrogen silsesquioxane (HSQ), methyl silsesquioxane (MSQ), poly(aryleneether)(PAE), parylene-N, parylene-F, Teflon(polytetrafluoroethlene;PTFE), amorphous carbon, amorphous fluorocarbon, porous SiCOH, porousMSQ, and porous PAE.
 6. The method of claim 1, wherein each of the firstand second bonding layers comprises silicon carbonitride (SiCN) orsilicon oxide (SiO₂).
 7. A method of manufacturing a semiconductordevice, the method comprising: sequentially forming a first interlayerinsulating layer, a first adsorption layer and a first bonding layer ona first substrate, the first adsorption layer including a low-kdielectric material and having a density lower than a density of thefirst bonding laver, forming a first conductive pattern through thefirst bonding laver, the first adsorption layer and a portion of thefirst interlayer insulating layer; sequentially forming a secondinterlayer insulating layer a second adsorption layer and a secondbonding layer on a second substrate, the second adsorption layerincluding a low-k dielectric material and having a density lower than adensity of the second bonding layer; forming a second conductive patternthrough the second bonding laver, the second adsorption layer and aportion of the second interlayer insulating layer; disposing the secondsubstrate on the first substrate so that the first and second bondinglayers contact each other, the first and second conductive patterns atleast partially overlap with each other in a vertical directionsubstantially perpendicular to an upper surface of the first substrate;and performing a heat treatment process on the first and secondsubstrates, wherein each of the first and second adsorption layersincludes at least one air gap penetrating therethrough.
 8. A method ofmanufacturing a semiconductor device, the method comprising: forming afirst interlayer insulating layer on a first substrate; forming a firstopening through the first interlayer insulating layer; forming a firstbonding layer on the first interlayer insulating layer, the firstopening being transformed into a first air gap; forming a firstconductive pattern through the first bonding layer and a portion of thefirst interlayer insulating layer; forming a second interlayerinsulating layer on a second substrate; forming a second opening throughthe second interlayer insulating layer; forming a second bonding layeron the second interlayer insulating layer, the second opening beingtransformed into a second air gap; forming a second conductive patternthrough the second bonding layer and a portion of the second interlayerinsulating layer; disposing the second substrate on the first substrateso that the first and second bonding layers contact each other, thefirst and second conductive patterns at least partially overlap witheach other in a vertical direction substantially perpendicular to anupper surface of the first substrate; and performing a heat treatmentprocess on the first and second substrates.
 9. The method of claim 8,wherein a lower surface of the first conductive pattern is exposed bythe first air gap, and a lower surface of the second conductive patternis exposed by the second air gap.
 10. The method of claim 8, wherein thefirst and second conductive patterns do not contact each other beforeperforming the heat treatment process.
 11. The method of claim 8,wherein the first and second conductive patterns contact each otherafter performing the heat treatment process.
 12. The method of claim 8,wherein forming the first conductive pattern includes: forming a firstetch stop layer on the first bonding layer; forming a third openingthrough the first etch stop layer, the first bonding layer and theportion of the first interlayer insulating layer; forming a firstconductive layer on the first etch stop layer to fill the third opening;and performing a polishing process on the first conductive layer untilan upper surface of the first etch stop layer is exposed.
 13. The methodof claim 12, wherein the third opening is connected to the first airgap.
 14. The method of claim 8, wherein forming the second conductivepattern includes: forming a second etch stop layer on the second bondinglayer; forming a fourth opening through the second etch stop layer, thesecond bonding layer and the portion of the second interlayer insulatinglayer; forming a second conductive layer on the second etch stop layerto fill the fourth opening; and performing a polishing process on thesecond conductive layer until an upper surface of the second etch stoplayer is exposed.
 15. The method of claim 14, wherein the fourth openingis connected to the second air gap.
 16. A method of manufacturing asemiconductor device, the method comprising: sequentially forming afirst interlayer insulating layer, a first diffusion barrier layer, afirst adsorption layer and a first bonding layer on a first substrate,the first adsorption layer including a low-k dielectric material, andthe first diffusion barrier layer having a density higher than a densityof the first adsorption layer; forming a first conductive patternthrough the first bonding layer, the first adsorption layer, the firstdiffusion barrier layer and a portion of the first interlayer insulatinglayer; sequentially forming a second interlayer insulating layer, asecond diffusion barrier layer, a second adsorption layer and a secondbonding layer on a second substrate, the second adsorption layerincluding a low-k dielectric material, and the second diffusion barrierlayer having a density higher than a density of the second adsorptionlayer; forming a second conductive pattern through the second bondinglayer, the second adsorption layer, the second diffusion barrier layerand a portion of the second interlayer insulating layer; disposing thesecond substrate on the first substrate so that the first and secondbonding layers contact each other, the first and second conductivepatterns at least partially overlap with each other in a verticaldirection substantially perpendicular to an upper surface of the firstsubstrate; and performing a heat treatment process on the first andsecond substrates, wherein each of the first and second adsorptionlayers includes at least one air gap extending therethrough.
 17. Themethod of claim 16, wherein the first adsorption layer has a densitylower than a density of the first bonding layer, and the secondadsorption layer has a density lower than a density of the secondbonding layer.
 18. The method of claim 16, wherein the first and secondconductive patterns do not contact each other before performing the heattreatment process, and wherein the first and second conductive patternscontact each other before after performing the heat treatment process.